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Abstract:

A system and method for cooling an internal combustion engine. In one
embodiment of the invention a cooling system for an internal combustion
engine is disclosed, comprising an engine; an intercooler for receiving
combustion air from a turbocharger, the intercooler comprising an
air-to-liquid heat exchanger for exchanging heat between the combustion
air and a liquid coolant; an intercooler radiator; at least one engine
coolant radiator; an expansion tank; an oil cooler; and at least one
pump, wherein the dedicated fan is controlled by a temperature switch or
controller and wherein the at least one engine coolant radiator and the
intercooler radiator are located on opposite sides of the engine.

Claims:

1. A cooling system for an internal combustion engine comprising: an
engine; an intercooler for receiving combustion air from a turbocharger,
the intercooler comprising an air-to-liquid heat exchanger for exchanging
heat between the combustion air and a liquid coolant; an intercooler
radiator comprising: a heat exchanger for exchanging heat between the
liquid coolant and ambient air; and a fan.

2. The cooling system of claim 1, wherein the fan is controlled by a
temperature switch or a microprocessor controller.

3. The cooling system of claim 2, wherein the temperature switch
comprises a temperature sensor which detects a temperature of the liquid
coolant.

4. The cooling system of claim 3, wherein the temperature switch or
controller energizes the fan when the temperature of the liquid coolant
is within a specified range of temperatures.

5. The cooling system of claim 3, wherein the temperature switch or
controller de-energizes the fan when the temperature of the liquid
coolant is within a specified range of temperatures.

6. The cooling system of claim 1, further comprising: at least one engine
coolant radiator; an expansion tank; an oil cooler; and at least one
pump.

7. The cooling system of claim 6, wherein the at least one engine coolant
radiator and the intercooler radiator are located on opposite sides of
the engine.

8. The cooling system of claim 6, further comprising an intercooler pump
between the expansion tank and the intercooler radiator.

9. The cooling system of claim 8, wherein the intercooler pump is
connected with an output of the expansion tank and an outlet of the
intercooler.

10. The coating system of claim 9, wherein the expansion tank outputs
liquid coolant to both the at least one pump and the intercooler pump.

11. A cooling system for an internal combustion engine, comprising: an
engine cooling loop, comprising: an engine; a control valve; at least one
engine coolant radiator; an engine coolant expansion tank; and an engine
coolant pump. an intercooler loop, comprising: an intercooler for
receiving combustion air from a turbocharger, the intercooler comprising
an air-to-liquid heat exchanger for exchanging heat between the
combustion air and a liquid coolant; a first intercooler radiator
comprising a heat exchanger for exchanging heat between the liquid
coolant and ambient air; an intercooler pump; and an intercooler loop
expansion tank.

12. The cooling system of claim 11, wherein the control valve operate to
selectively distribute liquid coolant between at least one engine
radiator and the engine coolant expansion tank.

13. The cooling system of claim 12, wherein the at least one engine
coolant radiator and the first intercooler radiator comprise a radiator
bank cooled by at least one shared fan.

14. The cooling system of claim 13, wherein the intercooler loop further
comprises a second intercooler radiator.

15. The cooling system of claim 14, wherein the second intercooler
radiator is cooled by a second dedicated fan

16. The cooling system of claim 15, wherein the second dedicated fan is
controlled by a temperature switch or a microprocessor controller.

17. The cooling system of claim 16, wherein the temperature switch
comprises a temperature sensor which detects a temperature of the liquid
coolant.

18. The cooling system of claim 17, wherein the temperature switch or
controller energizes the fan when the temperature of the liquid coolant
is within a specified range of temperatures.

19. A cooling system for an internal combustion engine comprising: an
engine; an intercooler for receiving combustion air from a turbocharger,
the intercooler comprising an air-to-liquid heat exchanger for exchanging
heat between the combustion air and a liquid coolant; an intercooler
radiator comprising: a heat exchanger for exchanging heat between the
liquid coolant and ambient air and a fan; at least one engine coolant
radiator; an expansion tank; an oil cooler; and at least one pump,
wherein the fan is controlled by a temperature switch or a microprocessor
controller, wherein the temperature switch comprises a temperature sensor
which detects a temperature of the liquid coolant, wherein the
temperature switch or controller energizes the fan when the temperature
of the liquid coolant is within a specified range of temperatures,
wherein the temperature switch or controller de-energizes the fan when
the temperature of the liquid coolant is within a specified range of
temperatures.

20. The cooling system of claim 19, wherein the at least one engine
coolant radiator and the intercooler radiator are located on opposite
sides of the engine.

Description:

TECHNICAL FIELD

[0001] The present invention is in the field of locomotive diesel engines
and cooling systems. More particularly, the present invention is in the
technical field of cooling systems for diesel engines utilizing multiple
flow paths to provide flexibility, efficiency and reduced emissions.

BACKGROUND OF THE INVENTION

[0002] Cooling systems for internal combustion engines, such as those
powering locomotives, are known in the art for the purpose of maintaining
engine temperature and lubricating oil temperatures within desired
operating parameters. In addition, the cooling system is used to reduce
the temperature of the charge air. In typical cooling systems, ambient
air is forced through heat exchangers and the cooling capability is
constrained by the temperature of the ambient air as well as other
factors. There are two common types of cooling systems commonly found in
locomotives.

[0003] For example, the first type of cooling system consists of a
Y-shaped pipe on the engine which splits the coolant flow into two
radiators. The coolant exits both the radiators and enters an oil cooler,
which is in parallel to an expansion tank. From the oil cooler the
coolant is combined with the outlet of the expansion tank and then it
enters a pair of pumps that are mounted on the engine block. The pumps
then circulate the coolant through fluid passages within the engine. Some
of the fluid flows through passages in the cylinder liners and heads
while the remainder exits the engine at the opposite end of the pumps and
enters a pair of intercoolers that are located on each side of the
engine. After the coolant absorbs the heat from the intercooler, it then
re-enters the engine via another fluid passage and combines with the
fluid coming from the cylinder liners and heads. The coolant then exits
the engine and is diverted through the Y-shaped pipe to the radiators
restarting the cooling process.

[0004] The above prior art cooling system allows the engine cylinder
liners, cylinder heads, oil cooler and the intercoolers and crankcase
exhaust elbows that are located in the upper deck of the crankcase to be
maintained at acceptable temperature levels. The coolant temperature is
at its lowest as it is coming out of the radiators, and this coolant is
provided to the oil cooler. As the coolant continues through the system
and flows through the engine and intercoolers, it may warm up
considerably and not lose heat until it once again passes through the
radiators. In this typical prior art cooling system, the engine coolant
enters the engine around 180 degrees Fahrenheit and exits the engine
around 190 degrees Fahrenheit.

[0005] The second type of prior art cooling system is similar to the first
type with the exception that the coolant flows out of the engine through
a water discharge header and is combined with coolant that exits from the
intercooler and turbocharger. The coolant then enters a control valve
that will either direct the coolant to the radiator or expansion tank
depending upon the temperature of the coolant. If the coolant is warm, it
will be directed to the radiators and then to the expansion tank. The
coolant then passes through the oil cooler to a pump which circulates the
coolant through the water inlet header into the engine turbocharger and
intercoolers. If the coolant temperature is cold, which is typical during
engine start up, the control valve shall route the coolant such that it
bypasses the radiators, and flows directly into the expansion tank, and
continues the process as described above. This type of cooling system is
designed to maintain a coolant temperature between 182 degrees Fahrenheit
and 200 degrees Fahrenheit.

[0006] These traditional cooling systems of the prior art have a
disadvantage because these systems do not allow the flexibility to
provide a lower coolant temperature to the intercoolers. The lowest
coolant temperature that is received by the intercoolers of both systems
is dictated by the coolant temperature that is required by the cylinder
liners and cylinder head.

[0007] The disclosed split cooling system and method is directed to
overcoming one or more of the disadvantages listed above.

SUMMARY OF THE INVENTION

[0008] In one aspect, the present invention disclosed herein is directed
to a cooling system for an internal combustion engine, comprising an
engine; at least one intercooler for receiving combustion air from a
turbocharger, the intercooler comprising an air-to-liquid heat exchanger
for exchanging heat between the combustion air and a liquid coolant; an
intercooler radiator; at least one engine coolant radiator; an expansion
tank; an oil cooler; and at least one pump, wherein the dedicated fan is
controlled by a temperature switch or microprocessor controller and
wherein the at least one engine coolant radiator and the intercooler
radiator are located on opposite sides of the engine.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] FIG. 1 is a diagram of a prior art cooling system for a diesel
locomotive engine.

[0010] FIG. 2 is an diagram of another prior art system for a diesel
locomotive engine

[0011] FIG. 3 is a diagram of a cooling system for a diesel locomotive
engine according to one embodiment the present invention.

[0012] FIG. 4 is a diagram of a cooling system for a diesel locomotive
engine according to another embodiment of the present invention.

[0013] FIG. 5 is a diagram of a cooling system for a diesel locomotive
engine according to an alternative embodiment of the present invention.

[0014] FIG. 6 is a diagram of a cooling system for a diesel locomotive
engine according to another embodiment of the present invention.

[0015] FIG. 7. is a diagram of a cooling system for a diesel locomotive
engine according to another embodiment of the present invention.

[0017] Referring to FIG. 1, a typical prior art cooling system 100 is
depicted. Cooling system 100 may include an engine 102, at least one
intercooler 104, at least one radiator 106, an expansion tank 108, an oil
cooler 110, and at least one pump 112. Cooling system 100 is generally
utilized to maintain certain optimal temperatures of various components
in cooling system 100 by circulating a liquid coolant, such as water that
may include chemical additives such as anti-freeze and corrosion
inhibitors. Cooling system 100 also includes piping for interconnecting
the various components of the system and associated valves, as will be
described more fully below.

[0018] Engine 102 includes internally formed cooling passages and/or a
water jacket through which the some of the liquid coolant flows and
absorbs energy from engine 102, thereby cooling engine 102. At least one
pump 112 is used to circulate the liquid coolant throughout cooling
system 100, as described below.

[0019] The remainder of the liquid coolant exits engine 102 and is
directed to at least one intercooler 104, said intercooler used to
improve the volumetric efficiency of engine 102 by increasing the intake
air charge density. For example, as air is compressed in the turbocharger
(not shown), the temperature of the air increases, which consequently
decreases the air density of the charge air delivered to the cylinders in
engine 102. This hotter, less dense air decreases combustion efficiency.
In order to increase combustion efficiency, at least one intercooler 104
lowers the temperature of the charge air to increase the air's density,
which in turn increases combustion efficiency. Intercooler 104 may be a
charge air cooler which utilizes an air-to-liquid heat exchange device.
As the liquid coolant flows through intercooler 104, heat may be
transferred from intercooler 104 to the liquid coolant. After the liquid
coolant exits intercooler 104, it is directed back into engine 102, where
it enters another fluid passage and combines with the coolant that has
passed through the water jacket.

[0020] After the liquid coolant exits engine 102, it may be diverted by a
Y-pipe device 114 into at least one parallel flow path. In the prior art
cooling system 100 shown in FIG. 1, device 114 is a Y-pipe which
separates the liquid coolant into two parallel flow paths. However, any
number of parallel flow paths may be utilized. After the liquid coolant
travels through the Y-Pipe device 114 (if used) and is diverted into the
appropriate number of flow paths, it next enters at least one radiator
106.

[0021] Radiator 106 may be a heat exchange device of any type used in the
art of engine cooling systems. As the liquid coolant flows through at
least one radiator 106, at least one fan 116 will provide an increased
air flow through radiator 106 and the liquid coolant will lose some its
accumulated heat and return to a lower temperature. As the cooler liquid
coolant exits at least one radiator 106, at least a portion of the liquid
coolant is directed to oil cooler 110. Oil cooler 110 is another heat
exchange device used to maintain the lubricating oil for engine 102 at an
optimal temperature. The remainder of the liquid coolant not directed to
oil cooler 110 may be directed to expansion tank 108.

[0022] As the liquid coolant exits oil cooler 110, it may be combined with
the outlet of expansion tank 108, and the combined liquid coolant flow
path may then enter at least one pump 112. At least one pump 112 may be
mounted on engine 102. At least one pump 112 may then circulate the
liquid coolant through engine 102, restarting the cooling cycle described
above.

[0023] Referring now to FIG. 3, one embodiment of a system of the present
invention is depicted. As shown in FIG. 3, one aspect of the present
invention is an extension of the intercooler loop of the prior art.
Cooling system 200 includes an intercooler radiator 220 on the opposite
end of engine 102 from at least one radiator 106. Upon exiting the engine
102 liquid coolant passes through the intercooler radiator 220 before
entering at least one intercooler 104. The intercooler radiator 220 may
be cooled by ambient air provided by a dedicated fan 222. Dedicated fan
222 provides an ambient air path for intercooler radiator 220 that is
independent of the ambient air path provided by the at least one fan 116
of the at least one radiator 106. The liquid coolant would then be
returned to engine 102 from intercooler 104 and continue the cooling
system process as described above in reference to FIG. 1. The dedicated
fart 222 for intercooler radiator 220 may be controlled by a temperature
switch or microprocessor controller. For example, in one embodiment of
the present invention, the temperature switch may energize dedicated fan
222 when the liquid coolant temperature is above 150 degree Fahrenheit
and may de-energize dedicated fan 222 when the liquid coolant temperature
is below 140 degrees F. The temperature switch may receive the
temperature input from a temperature sensor located within cooling system
200. In one embodiment, the temperature sensor is located between engine
102 and intercooler radiator 220.

[0024] One feature of the present invention is that the additional split
cooling loop provided by intercooler radiator 220 provides a lower
temperature liquid coolant to the at least one intercooler 104. As
explained above in reference to FIG. 1, at least one intercooler 104 cook
the charge air to increase the charge density. This higher air density
increases combustion efficiency. In the prior art cooling system 100
shown in FIG. 1, the amount of cooling by the at least one intercooler
104 is limited by the temperature of the liquid coolant as dictated by
the optimum cylinder liner and cylinder head temperatures. This is
because the liquid coolant flows directly from engine 102 to at least one
intercooler 104. In the present invention, however, the liquid coolant is
cooled by the intercooler radiator 220 after it leaves engine 102 but
before it enters at least one intercooler 104. It is advantageous to
provide this cooler liquid coolant to the at least one intercooler 104 to
reduce the charge air temperature which will reduce the emissions from
engine 102. Another feature of the present invention is that the cooler
charge air results in lower fuel consumption.

[0025] Referring now to FIG. 4, another embodiment of the system of the
present invention is depicted. As shown in FIG. 4, another aspect of the
present invention may include an intercooler pump 312, either engine
driven or motor driven, which pumps the liquid coolant through
intercooler radiator 220 and intercooler 104, bypassing engine 102. There
may also be a connection from intercooler 104 to expansion tank 108,
bypassing radiator 106. There may also be a connection from expansion
tank 108 to the intercooler pump 312. The embodiment shown in FIG. 3 may
help ensure that intercooler radiator 220 and intercooler radiator fan
222 are on the opposite side of engine 102 from the at least one radiator
106.

[0026] Referring now to FIG. 5 an alternative embodiment of the system of
the present invention is depicted. As shown in FIG. 5, another aspect of
the present invention may include the alteration of the at least one
radiator 106 such that a radiator bank 502 is split to allow for the
cooling of both the engine coolant and intercooler coolant. The existing
shared fan 116 would provide ambient cooling air for both at least one
radiator 106 and the intercooler radiator 220. The intercooler coolant
would then proceed to another dedicated intercooler radiator 520 that is
cooled with ambient air supplied by a dedicated fan 516. Upon exiting the
intercooler radiator 520, the coolant would then proceed to another
expansion tank 508. It would then be pumped via a dedicated pump 512 and
on to the intercooler 104 to repeat the process.

[0027] Referring now to FIG. 6, an alternative embodiment of the present
invention is depicted. As shown in FIG. 6, this embodiment is a variation
of invention as depicted in FIG. 4. After exiting the intercooler 104,
the coolant is directed to the at least one radiator 106, bypassing the
engine 102, expansion tank 108 and separate intercooler pump 312. The
coolant that enters the expansion tank 108 is split upon exiting the
expansion tank 108 where some of the coolant is directed to the engine
102 and the remainder is directed to the intercooler pump 312, where it
re-starts the intercooler cooling process.

[0028] Referring now to FIG. 7, an alternative embodiment of the present
invention is depicted. As shown in FIG. 7, this embodiment is a variation
of invention as depicted in FIG. 5. This variation does not include a
separate fan for the intercooler radiator 220, but utilizes the
distinctly separate coolant loop with at least one intercooler radiator
220 for the intercooler loop and uses at least one fan 116 that provides
ambient cooling air for both the intercooler radiator 220 and the
radiator 106. As in FIG. 5, this embodiment also contains a separate
expansion tank 508 and pump 512 for the intercooler coolant loop.

[0029] The embodiments described above are given as illustrative examples
only. It will be readily appreciated by those skilled in the art that
many deviations may be made from the specific embodiments disclosed in
this specification without departing from the invention. Accordingly, the
scope of the invention is to be determined by the claims below rather
than being limited to the specifically described embodiments above.